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Congressional Testimony
Health Impacts of Incineration - Part II

Congressional Testimony by
Barry L. Johnson, Ph.D.
Assistant Surgeon General
Assistant Administrator
Agency for Toxic Substances and Disease Registry
Public Health Service
U. S. Department of Health and Human Services

Before the
Subcommittee on Human Resources
and Intergovernmental Relations
Committee on Government Operations
United States House of Representatives

July 8, 1994

Good morning. I am Barry Johnson, Ph.D., Assistant Administrator, Agency for Toxic Substances and Disease Registry (ATSDR). I am accompanied today by Maureen Lichtveld, M.D., Chief Biomedical Officer for Public Health Practice, ATSDR. We welcome this opportunity to present testimony on the health impacts of incineration: what we do and do not know. Our testimony is derived from ATSDR's responsibilities and findings under the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (CERCLA, or Superfund), and the Resource Conservation and Recovery Act (RCRA, Section 3019).

In testimony presented by ATSDR before this Subcommittee on January 24, 1994, we responded to eight issues related to our experience with the health impacts of incinerators. Our testimony today will elaborate on the January testimony and respond to your request for an update on research needed on incineration of municipal waste. As the Subcommittee knows, there are many scientific, technology, and policy issues that attend incineration of wastes. Our focus will be on the public health issues.

Many communities have expressed their concerns about the potential implications of incineration of wastes to ATSDR. Their concerns are usually expressed as questions about the associations between incineration of wastes and possible health effects. We are often unable to answer those questions. Scientific information on the human health impacts of incineration isn't often available because the relevant studies haven't been conducted.

To achieve a true public health perspective, incineration of wastes should be viewed in the larger context of generation and management of wastes. Wastes become a public health concern when they are disposed of and improperly managed. Therefore, in a public health context, the most protective action is not to produce waste. Waste elimination or minimization equates with prevention or reduction of the health consequences of wastes.

When wastes are generated, the question becomes how to dispose of them in ways that do not harm the public's health or the environment. Incineration has been one means of disposing of wastes. The permitting of incinerators is handled by government regulatory agencies. Analysis of health and environmental impacts is normally conducted by assessing the risk associated with incinerators proposed for specific applications. These risk assessments consider the toxicologic data on substances assumed to be emitted from the incinerator under operating conditions.

ATSDR has had some experience in working on health issues pertaining to incineration of wastes. Examples of our activities related to incineration of wastes follow.

In particular, I draw your attention to a consultation requested of ATSDR by Senator Lugar and Congressman McCloskey of Indiana concerning incineration of PCB-contaminated wastes in Bloomington, Indiana. They asked ATSDR to review the health implications of incinerating PCB-contaminated soil from the Bloomington area. In response, ATSDR convened 40 national experts in the fields of combustion engineering, toxicology, epidemiology, medicine, chemistry, and related fields to review the scientific literature on incineration of wastes, the health effects of PCBs, and nonincineration means of disposing of PCB-contaminated wastes. Reports from these three panels are in peer review, and ATSDR will be pleased to make them available to the Subcommittee when they have been completed. A few pertinent preliminary findings from this report are included in this testimony under the section "The Public Health Impact of Older Municipal Solid Waste Incinerators."

ATSDR has also investigated the effects on community health of an incinerator in North Carolina. The Caldwell Systems incinerator disposed of industrial solvents and hazardous wastes in the 1970s and 1980s. This incinerator appears to have been operated beyond its operating capacity, resulting in incomplete combustion of hazardous wastes. ATSDR was asked by a local physician and EPA Region IV to evaluate the health problems of residents living in the vicinity of the incinerator. ATSDR's investigation found an increased pattern of respiratory problems in community residents. In addition, residents complained about irritation of the airways and poor motor coordination. A follow-up study is currently underway to evaluate better the health problems reported by the residents; its focus is on determining the presence of adverse health effects of the pulmonary, neurobehavioral, and immune systems. The field work for this study has been conducted and ATSDR is currently analyzing the data.

In Arkansas, the community living near the Vertac Superfund site incinerator expressed to the Arkansas Department of Health (ADD) concerns about the public health impact of the facility. To assist ADD, ATSDR awarded two grants to conduct an exposure study and a reproductive outcome study. Preliminary findings from the exposure study indicate an association between elevated body burdens of certain compounds (2,4-T and dioxin) and length of residence near the site. This constitutes historical, pre-incineration exposure. The incinerator is currently operating. A second round of testing was conducted in March 1994 to assess exposures to the chemicals incinerated to date. Following completion of the incineration of the dioxin-containing wastes, a third round of testing will be conducted.

ATSDR is also supporting a Health and Clean Air Study conducted by the University of North Carolina. The study will further explore the occurrence of and risk factors for lung and respiratory diseases potentially caused by hazardous substances. The study compares residents of communities near a municipal solid waste incinerator, a medical waste incinerator, and a hazardous waste incinerator with three nearby control populations, over 3 years. Components of the study include baseline spirometry, peak flow measurements, nasal lavage, and a survey to collect information about respiratory symptoms and outcomes. Data collection for this study is in its third year.

At another site, at the request of local citizens, ATSDR reviewed the location, design, and operating plans for a temporarily sited incinerator proposed for placement at the Brio Superfund site near Houston, Texas. Because ATSDR was not a party to considering other remedial options, our consultation was confined to the health issues attending incineration. ATSDR advised EPA to move the location of the proposed incinerator away from residential areas, to increase off-site emissions monitoring during the incinerator's operation, to conduct additional characterization of on-site contaminants, and to develop a means of sharing the monitoring data with local residents. In addition, ATSDR has undertaken a comprehensive health study in the community. The purposes of the study are to determine a) if there is an increased reporting of health effects by the current residents; b) if subtle adverse health effects have occurred in some organ systems (kidney, liver, and immune); and c) the occurrence of birth defects in children born to mothers who lived near the Brio site. The report discussing the first phase of the study will be available for public release within 1 month.

Earlier this year, EPA Region V, State and local health departments, and the local community requested ATSDR's assistance in addressing health concerns associated with a municipal waste incinerator in Columbus, Ohio. The Columbus Municipal Waste Facility is a waste-to-energy facility in Columbus, Ohio, where municipal trash is burned in boilers to generate energy. It has operated since December 1983. Of particular concern to residents is the fact that analysis of past samples has identified dioxin compounds in the stack emissions. Currently, ATSDR is working with other federal, state, and local agencies and the community to develop a plan of action for evaluating the residents' health concerns.

ATSDR is assisting EPA Region III in addressing the health concerns of residents living in two heavily industrialized communities in southwest Philadelphia and Chester, Pennsylvania. ATSDR was also petitioned by a citizen living in southwest Philadelphia to address the health concerns of the two communities. Residents are concerned that the proliferation of industries is polluting the air and creating an inordinate threat to their health. In addition, officials are considering establishing a new hazardous waste incinerator in Chester.

ATSDR is concerned about the public health impact of such multiple emission sources and the resulting exposures to hazardous substance mixtures. These concerns are heightened when communities may be disadvantaged and underserved. As a result, the Agency is reviewing methods for determining which adverse health conditions may be present at higher rates in disadvantaged, underserved, and minority communities to assess whether exposures to hazardous substances in the environment are impacting the public health.

The Public Health Impact of Older Municipal Solid Waste Incinerators

In your letter of invitation, you asked us to address the health impacts on communities of an older municipal solid waste incinerator, like the one in Greenpoint.

The public health impact of incinerators can be influenced by the age of the equipment. Older incinerators, unless they have been upgraded in the past few years, may not have the most recent pollution control equipment and operating technologies; therefore, these incinerators may not be able to achieve the same level of emission control as a new municipal solid waste incinerator. In addition, in some instances, older incinerators may be operating under less stringent permits than those currently required by the EPA and State and local regulatory agencies. ATSDR supports the efforts by EPA in recent years to impose greater regulatory control over all forms of incineration, including municipal solid waste incineration, and to require incinerators to upgrade to the maximum achievable emissions control.

Some preliminary findings from the expert panels convened recently to assist ATSDR in evaluating the public health implications associated with incinerating PCB-contaminated waste in Bloomington, Indiana, are applicable to incineration in general. For example, the panels stressed the importance of evaluating information related to all aspects of the facility operations, design, and maintenance, including stack emissions data, when assessing the public health implications of incineration.

Moreover, the panels highly recommended the need for epidemiological studies to measure exposures and specific adverse health outcomes. To enhance our collective knowledge about the health impact of incineration, a recommendation was also made to establish relevant toxicological and environmental databases.

Health Impacts from Incinerator Emissions

Emissions of hazardous substances from incinerators are of particular concern to communities.

However, there are very few data on the impact of incinerator emissions on the health of nearby communities. Epidemiologic investigations have rarely been conducted and few studies of disease and illness patterns have been undertaken. For example, ATSDR staff recently searched the 10 most frequently used computerized environmental databases. More than 1 million entries were identified. Approximately 72,000 of the entries dealt with incineration. Of those, only a single entry included information about a population-based study conducted in a community living in the vicinity of an incinerator. That study of residents living near the Caldwell Systems incinerator in North Carolina was conducted by ATSDR. The findings from the Caldwell study were previously described in this testimony.

In the absence of human health data on the effects of a hazardous substance on public health, we rely on toxicity data. The effect of any toxic substance depends on factors such as duration of exposure, concentration of the substance in the environment, biological uptake, and personal susceptibility factors (e.g., age). All of these factors have to be considered in any estimate of the public health impact of incinerator emissions.

Much is known about the toxic effects of contaminants that may be released from waste incinerators, lead, mercury, dioxin, and furans. Scientific literature is available on each substance. This knowledge is based on laboratory animal studies, occupational investigations, and some community health studies. For example, lead exerts toxic effects on the nervous system, kidney, immune function, and reproduction. It is associated with hypertension in middleaged persons. Mercury or mercury compounds are toxic to the nervous system, kidney, and immune function. Data from epidemiologic studies and the scientific literature indicate that human exposure to PCBs may result in cancers of the hepato-biliary tract, as well as reproductive/developmental, dermatologic, cardiovascular, hepatic, and endocrine/thyroid effects. Dioxins have been extensively studied in toxicological studies. The most toxic member of the family of compounds called dioxins is 2,3,7,8-TCDD. What is known about human health effects has come primarily from occupational studies of workers. TCDD has been associated with chloracne, metabolism alterations, soft tissue sarcoma, and altered reproductive hormone levels. EPA lists TCDD as a probable human carcinogen. EPA is currently completing a reassessment of the human health risk of dioxin. Furans have been associated with dermal, ocular, and neurologic effects in humans.

Few data are documented in the scientific literature on specific interactions of the contaminants released from waste incinerators. In the absence of specific studies of combined contaminants, and because of our limited understanding of the mechanisms of actions of some substances, it is prudent to assume that the effects of exposure to these contaminants are additive.

It is important to emphasize that almost all of our toxicologic data are from studies in which exposure levels greatly exceeded those typical of incinerator releases.

Adequate information does not exist to support speculation on what, if any, human health effects might be associated with incinerator emissions. However, our experience with public health effects related to hazardous waste sites suggests the need to conduct two types of human health investigations. One type of investigation would look at cancer, birth defects, and respiratory disease rates in areas believed to be impacted by releases from incinerators. These studies would combine health data from many geographic areas. A second type of study would be site specific. Community health surveys would help clarify whether any unusual exposure or morbidity might be associated with exposure to substances from a given incinerator.

The Sensitivity of Various Populations-Because of Age, Gender, or Ethnic Background-to These Chemicals

Of special concern because of their risk for adverse health impacts from exposure to hazardous substances are sensitive subpopulations.

Infants and children. Of all human populations, infants and children are arguably most sensitive to toxic exposures. They are at special risk because they play outdoors; they ingest or mouth foreign objects; they are smaller (greater chemical doses per pound) than adults; they breathe more air (greater volume and breathing rate per pound) than adults; they are nutritionally challenged (because of protein-calorie requirements to support rapid physical growth); and they are undergoing developmental changes that make them especially vulnerable to chemical exposures. Moreover, they have the longest life expectancies, during which long-term adverse health effects may become manifest. Certain disorders may not become evident until a child reaches a particular developmental stage, which may be long after damage has been done. Some of the largest environmental health programs (e.g., lead, asbestos) are directed primarily at children.

People of reproductive age. All women of reproductive age must be included in this population because the most severe effects usually occur during the very early stages of pregnancy, often before a woman knows she is pregnant. In addition, pregnant women, especially those with multiple pregnancies, and the developing fetus have increased protein-calorie requirements to support rapid physical growth.

The developing fetus is particularly sensitive to chemical exposures. Exposure to chemicals has the greatest impact on those functions undergoing the most active development at the time of exposure. Animal studies and some human studies show that there are critical fetal developmental stages during which chemical exposure can cause permanent and devastating effects.

A small, but growing, scientific literature suggests that some toxicants affect male reproductive processes. For example, laboratory animal studies have shown that exposure to lead causes adverse reproductive outcomes in male rats, leading to neurologic effects on their offspring. Similarly, PCB exposures in fish and waterfowl have been reported to cause feminine features in males of these species.

Elderly persons and persons with chronic illnesses. Elderly persons and the chronically ill tend to be more susceptible to respiratory irritants. Long-standing public health policies, such as immunization guidelines for influenza, support this notion.

The elderly are also often nutritionally challenged because of reduced protein-calorie intake and the metabolic changes that occur during this life stage. Underlying illnesses, as in the case of the chronically ill may increase their susceptibility to particular toxicants. For example, persons with chronic diseases of the kidney system may experience more harmful effects from exposure to renal toxicants, such as lead and cadmium, compared with a healthy individual.

Moreover, elderly persons and those with chronic illnesses are often socially isolated and potentially less aware of environmental emergencies. Because of physical challenges, they may require special services during evacuation in the event of such an emergency.

Minorities. Preventing adverse health effects in minority populations exposed to hazardous substances is a priority for ATSDR. Minority populations, particularly African Americans, Hispanics, and Native Americans, suffer disproportionately from preventable morbidity and mortality. Regardless of income, education, or geographic location, these populations are often in poorer health than their white counterparts. This disparity is often associated with inadequate access to health care?for preventive services as well as for early diagnosis and treatment of disorders that may be associated with exposure to hazardous substances. Disadvantaged economic status also frequently affects nutritional status. Occupational chemical exposures may increase this population's susceptibility to adverse health effects resulting from other exposures to hazardous substances. In addition, certain pre-existing genetic disorders (G6-PD deficiency, sickle cell anemia) may compound the impact of such exposures.

Research Gaps

As a followup to ATSDR's testimony in January, an outline of relevant research was provided to address the lack of studies on any associations between emissions from municipal waste incinerators and human health effects. We continue to believe that the following areas need to be addressed:

1. Human studies would assess the health of persons around a representative sample of operating municipal waste incinerators. The adverse health effects emphasized during the study would include cancer, birth defects, and reproductive disorders, and lung and respiratory diseases (particularly asthma). Because municipal waste incinerators are often found in densely populated areas, and because many urban areas are populated by persons with diverse cultural and racial backgrounds, evaluating the effects of incinerator emissions on minorities and groups with diverse cultural backgrounds would be emphasized. Moreover, individuals with particular susceptibility (young children, pregnant women, and persons with health disabilities) would be given priority for study.

   Cancer and birth defects and reproductive outcomes can be evaluated using available health information and an ecologic or geographically based cross-sectional approach. The choice and number of incinerators studied would be based on the presence of good health outcome data (preferably disease incidence registries) and historical air monitoring data. As a basic study, case rates could be calculated for geopolitical units near the incinerator sites and compared with reference rates. Lung and respiratory diseases, for which there are no databases of information, would be evaluated by defining a population of people with asthma (or other chosen respiratory disease) and without asthma. Those people would be monitored for up to 3 years to determine any adverse health effects and to correlate air quality with respiratory disease symptoms and pulmonary function measures. The human health studies would be conducted by university investigators through grants from the sponsoring Federal agency.

2. Toxicologic information would be collected and computer databases would be developed using data from Federal and State environmental agencies on emissions from operating municipal waste incinerators. The database would be queried to ascertain the most common mixtures of materials released from incinerators and to develop a toxicologic profile of how the key mixtures might express their toxicity. This work would be conducted by a private sector contractor.

3. The key toxicologic mixtures identified would be referred to the National Toxicology Program of the Public Health Service for laboratory investigation. A program of toxicological research would include broad screening for acute toxicological effects followed by more in-depth study of effects on organ function, relevant to the typical mixtures released from operating municipal incinerators. Of particular importance would be studies of effects on lung tissue and reproductive function. Depending on the outcome of screening studies, some mixtures would be tested for long-term carcinogenicity. This type of research normally takes 5 years.

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